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help me done Sections 2-4 please –> The GC-MS data will be available in 2 days and I will send it to you –> I dont’t have time to done it on time since i have a big midterm and i need to study
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Chemistry 242
Lab 1: Reduction of Camphor Report
2023-2024
LAB 1: REDUCTION OF CAMPHOR REPORT
Jay Bunning
Alt
Name____________________________________________
Section_______
GRADING – each section below is worth 1 point. You must earn 4 out of 5 points to get credit for this
lab report. You do not need perfect scores on each section to get credit for that section.
SECTION 1 – Notebook
Include all of your notebook pages for this experiment. Each of the following sections will be graded 0/1:
Goal
Safety information
Reaction table
Procedure
Data/observations
Actual
Conclusion
:
·
x108 %
yield
Theoretical
If 4 of the 6 notebook parts are successfully completed, you will get credit for this section.
SECTION 2 – Data.
Answer the following questions. If you get 2 of 3 pieces, you will get credit for this section.
0 084
1. (1 piece) Mass of raw product____________
Purity of borneol+isoborneol from GCg
MS___________
.
Mass of borneol+isoborneol (taking into account purity)
_________________
mp of product__________________
% yield of borneol+isoborneol ____________________
Show calculations. Note: Make sure your % yield calculation includes the GC purity of the
borneol/isoborneol. 450 mg of product that is 60% pure is actually only 270 mg of borneol/isoborneol
of Camphor > mol
02g
,
=
152
.
0 0013138
.
234
mol of
Camphor
1 equi
7
2. (1 piece) If your yield was below 30% or above 100% explain what went wrong and how it might be
fixed. If your yield was between 30% and 100%, state that.
3. (1 piece) If your mp was more than 10C off from the expected value explain what led to the low purity
and how it might be fixed. If your mp was within 10C, state that.
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Chemistry 242
Lab 1: Reduction of Camphor Report
SECTION 3 –Spectroscopy.
If you earn 4 of 6 pieces, you will get credit for this section.
2023-2024
3A – NMR (1 piece). Attach your NMR spectrum. Make sure all chemical shifts and integrations are
labelled for peaks above 3ppm. Draw the compound corresponding to the major product, and label the Hs
on the structure that corresponds to each peak above 3 ppm
3B – GC (2 pieces) . Include the GC for your reaction mixture and the summary sheet. On the GC, label
the peaks for camphor, borneol, and isoborneol. On the summary sheet, normalize your data so that the
sum of camphor, borneol, and isoborneol adds to 100%.
3C – MS (3 pieces) Attach the MS for camphor, borneol, and isoborneol. If 1 of these compounds is not
present, write that. On each MS, write the name of the compound, and circle the molecular ion peak. If
the molecular ion peak is not present, indicate where it should have been.
SECTION 4 –Analysis questions.
Answer the following questions. If you earn 4 of 5 pieces, you will get credit for this section.
1. (1 piece) What was the major product according to NMR? According to GC-MS?
2. (1 piece). Did your NMR and GC-MS match? If not, explain how you determined the actual major
product.
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Chemistry 242
Lab 1: Reduction of Camphor Report
3. (1 piece) Explain why the reaction showed the selectivity that it did.
2023-2024
4. (1 piece) The literature value for the chemical shift of the OH peaks in borneol and isoborneol are
roughly 2 ppm. What was your WebMO NMR chemical shift for the OH peak? If your WebMO
chemical shift for the OH peak was not accurate, provide an explanation for what likely went wrong.
(hint – what is the primary experimental factor that leads to a specific OH chemical shift)
5. (1 piece) Other than OH peaks, do you feel that WebMO is a useful tool for predicting the NMR
spectrum of borneol/isoborneol? Explain (1 sentence) your reasoning. Make sure you explicitly write any
data here that you are discussing.
SECTION 5 –Safety
You don’t have to submit anything. You will get credit as long as you were prepared for lab and
didn’t violate any lab safety policies
10
CHEMISTRY 242
Organic Chemistry Laboratory 2
Lab Manual
Lab 1 – Reduction of Camphor
Professor Lawrence Goldman
Professor Tomi Sasaki
Department of Chemistry
University of Washington
Chemistry 242
Lab 1: Reduction of Camphor
2023-2024
LAB 1: REDUCTION OF CAMPHOR
SCENARIO: After a successful first year working for Chem Corp, you’ve been promoted. Your
supervisor calls you into their office. “I think you’re doing a great job, so I have a more challenging task
for you. I’m curious about how the 3-dimensional shape of molecules can influence how they react. In
particular, consider the molecule camphor. It is a ketone, and ketones are flat which means they generally
give both stereoisomers of an alcohol when they are reduced.”
Your supervisor continues “But camphor is a very bulky ketone, so maybe it reacts differently. Your task
this week is to figure out how camphor behaves and why.” You eagerly accept the assignment. Your first
task will be to react the camphor with NaBH4 and purify it. Your second task will be to analyze the
reaction mixture to determine how the shape of camphor influences its reactivity.
THEORY:
You will confirm the reactivity of camphor using melting point, NMR, and GC-MS analysis. It will be
up to you to compare those techniques to determine which is providing you with the most useful data.
Reduction of carbonyls with metal hydrides (sources of H−) of the Group III elements, such as lithium
aluminum hydride LiAlH4 and sodium borohydride NaBH4, is a fundamental transformation in any
organic chemist’s toolkit. Though more powerful reducing agents, such as lithium aluminum hydride,
reduce a wider variety of functional groups, sodium borohydride is attractive for its ease of handling.
Frequently used in the reduction of ketones and aldehydes, sodium borohydride does not react as violently
with water, and may be used in alcohol-based solvents such as methanol unlike lithium aluminum hydride.
The mechanism of sodium borohydride reduction is shown on the next page. While a single molecule of
NaBH4 can react with multiple ketones, it is also decomposed by water. We will use methanol as the
solvent because NaBH4 is more soluble in it while not decomposing as rapidly. To avoid losing too much
NaBH4, we will use it in excess. The reaction proceeds via delivery of a hydride at the electrophilic carbon
of the ketone four times to generate a tetraalkoxyboron compound. This tetraalkoxyboron compound can
then be decomposed at elevated temperatures.
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Chemistry 242
Lab 1: Reduction of Camphor
2023-2024
H
R
R
O
O
H
R
H B H
H
Na
R
O
R
R
H
H B
H
Na H
H
H B
H H
Transition State
(R2CHO)4B-Na+
Repeat 3x
4 R’OH
R
O
R
3 equiv
R
O
O B O
O Na
R
R
H
R
R
H
(1)
Na
heat
R
R
H
R
4 R2CHOH
(R’O)4B-Na+
(1)
During the reduction of camphor, there are two potential stereochemical outcomes depending on whether
the hydride approaches from the same side of the 6-membered ring as the bridging carbon (exo approach),
or the opposite face (endo approach) of the molecule. Which will be preferred? In situations like this,
sterics can often predict which product will be more favored. If the hydride nucleophile has an “easier”
path of attack from 1 side, that will be the dominant mechanism and lead to the major, although not
exclusive, product. If that is the case, this would be a diastereoselective reaction. Contrast that with the
diastereospecific alkene bromination reaction which was only capable of yielding one product. In this lab
you will utilize GC/MS to determine the ratio of these products. It’s also highly advisable to build models
to see which attack, endo or exo, is preferred.
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Chemistry 242
Lab 1: Reduction of Camphor
2023-2024
From this point onward, you are responsible for knowing the information contained within the
Introduction to this manual, including the “Organic Chemistry Laboratory Safety,” “Laboratory
Notebooks,” “Chemistry Stockroom,” and “General Chemistry Review Material” sections.
Safety Information:
Sodium borohydride reacts vigorously with water; avoid mixing large amounts of it with aqueous
solutions. Other chemical hazards include acetone and methanol (both highly flammable). In the event
of an emergency in your hood (e.g. fire) close your hood sash, and alert your TA. In the event of a
chemical spill on your skin or clothing, or in the lab, immediately alert your TA.
Pre-lab Information: There are 2 prelab quizzes for this experiment. The first covers the experiment,
while the second covers NMR.
Reading: PLKE experiment 33 and techniques 20 (TLC), 22 (GC), and 28 (MS).
Notebook Notes: Make sure you include a reaction table including safety, amounts, and theoretical yield.
PROCEDURE
Work in pairs for this experiment.
Reduction: To begin, place 190-210 mg of camphor in a 25-mL Erlenmeyer flask and dissolve it in 5-7
mL of methanol. Add your spin vane, and stir the solution at room temperature until the camphor has
dissolved. Add 190-210 mg of sodium borohydride to the Erlenmeyer flask in two portions (about 100 mg
at first, then the remaining sodium borohydride; you may observe vigorous bubbling when adding it). Be
sure to cap the sodium borohydride when it is not in use, so that it does not become deactivated by
exposure to water! Likewise, put a watch glass over the reaction flask when you are not adding
reagents. Heat the flask in a water bath on a warm hot plate until the solution is boiling (hot plate should
be set to low or 2). Once the reaction is boiling, continue heating for 5 minutes, and then cool the reaction
back to room temperature (methanol boiling point is 65ºC).
Isolation of borneol and isoborneol: Cool your reaction in an ice bath, then add about 10 mL of ice-cold
DI water to the cooled reaction mixture. White solid should appear in the solution. Collect the white solid
by filtering on a Büchner funnel. Remember to wet the funnel paper with water before you filter. After
filtering, use 1-2 mL of cold DI water to rinse the sides of the reaction flask to get any additional product.
Filter this wash, and allow the product to air-dry on the vacuum for about 5 minutes. It is best to detach
the vacuum hose from your Büchner funnel before turning the vacuum off.
Purification and characterization: Rinse your solid product off of the filter paper with 7-9 mL hexanes
into a 25-mL Erlenmeyer flask or beaker. If necessary, add more hexanes until your product is fully
dissolved. Dry the solution over granular anhydrous sodium sulfate (see Technique 12, Section 12.9,
p.710). Vacuum filter the sodium sulfate out, then pour the hexanes solution into a pre-weighed 25 mL
Erlenmeyer flask (or beaker). In your hood, evaporate the hexanes using the air line. Prepare a melting
point
capillary
tube
and
obtain
the
mass
and
melting
point
of
your product.
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Chemistry 242
Lab 1: Reduction of Camphor
2023-2024
Prepare a GC-MS sample of your product, which will be used to determine the ratio of the borneol and
isoborneol in your product. Obtain a GC-MS vial. Dissolve
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